What about the person of whom I do not know the religion; do I consider him a disbeliever or not? May Allaah reward you!

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

The fact is we cannot grasp what the questioner means exactly. However, people in relation to belief and disbelief are of several types:

First, those people whose Islam has been affirmed; they cannot then be considered disbelievers unless they commit an act of disbelief and all the conditions of being punished for disbelief are met fully in them.

Second, those people whose disbelief has been affirmed, such as the Jewish and the Christian people and the like sects of disbelief; you can consider them disbelievers regardless of their religion.

Third, those whom we do not know whether they are believers or not;  they cannot be considered disbelievers until we know their condition well.

Allaah Knows best.